68 PRACTICAL POULTRY PRODUCTION 



Two coiled membraneous cords or layers of thick albumen 

 called chalazae are attached to the opposite ends of the 

 yolk with each end of the shell. The purpose of the chalazae 

 is to lessen the movement of the yolk so that its position 

 will be maintained in the center of the egg. The germ 

 spot, or blastoderm, is a small spot located on the upper 

 surface of the yolk. 



Figure 66. — Eggs showing variations in size and shape. Uniformity in size 

 and shape should be the guide in selecting hatching eggs. 



SELECTION AND CARE OF EGGS FOR HATCHING 



Fertility. The most important factor necessary to pro- 

 duce a good hatch is fertile eggs, produced by healthy, vigor- 

 ous stock properly mated and kept under the best possible 

 conditions. The temperature at which eggs are kept pre- 

 vious to hatching has, therefore, a determining influence on 



